勘察学课件：Exploration geology.ppt

1、ME551/GEO551 INTRODUCTION TO GEOLOGY OF INDUSTRIAL MINERALS SPRING 2011 BASIC CONCEPTS: GEOLOGY, MINING, AND PROCESSING OF THE INDUSTRIAL MINERALSVirginia McLemoreOUTLINE Definitions Life cycle of a mine Classification of reserves and resources Geology of industrial minerals Field notes SamplingDEFI

2、NITIONSA mineral occurrence is any locality where a useful mineral or material is found. A mineral prospect is any occurrence that has been developed by underground or by above ground techniques, or by subsurface drilling to determine the extent of mineralization. The terms mineral occurrence and mi

3、neral prospect do not have any resource or economic implications.A mineral deposit is any occurrence of a valuable commodity or mineral that is of sufficient size and grade (concentration) that has potential for economic development under past, present, or future favorable conditions. An ore deposit

4、 is a well-defined mineral deposit that has been tested and found to be of sufficient size, grade, and accessibility to be extracted (i.e. mined) and processed at a profit at a specific time. Thus, the size and grade of an ore deposit changes as the economic conditions change. Ore refers to industri

5、al minerals as well as metals.Generally, industrial minerals are any rock, mineral, or naturally occurring substance or closely related man-made material of economic value, generally excluding metals, fuels, and gemstones. “Without a market, an industrial mineral deposit is merely a geological curio

6、sity” Demand feeds back from the end-use market, to the end product, to the intermediate end product, and finally back to the mineral supplier. Customer specifications include physical and chemical and other criteriaClassification of mineral resources on U.S. Federal LandLocatable Minerals are whate

7、ver is recognized as a valuable mineral by standard authorities, whether metallic or other substance, when found on public land open to mineral entry in quality and quantity sufficient to render a claim valuable on account of the mineral content, under the United States Mining Law of 1872. Specifica

8、lly excluded from location are the leasable minerals, common varieties, and salableminerals.Leasable Minerals The passage of the Mineral Leasing Act of 1920, as amended from time to time, places the following minerals under the leasing law: oil, gas, coal, oil shale, sodium, potassium, phosphate, na

9、tive asphalt, solid or semisolid bitumen, bituminous rock, oil-impregnated rock or sand, and sulfur in Louisiana and New Mexico.Salable Minerals The Materials Act of 1947, as amended, removes petrified wood, common varieties of sand, stone, gravel, pumice, pumicite, cinders, and some clay from locat

10、ion and leasing. These materials may be acquired by purchase only. LIFE CYCLE OF A MINEStages of Mining Exploration (discovery) Feasibility study Mine development Extraction/production Processing/beneficiation/milling Marketing Closure/post-mining usehttp:/www.mndm.gov.on.ca/mndm/mines/mg/mgimages/c

11、ycle_e.pdfEXPLORATIONExploration identification of areas with potential for discovery of an economic mineral deposit geology governs the quest surveys sampling geophysics drilling pits shafts, adits base-line/pre-existing conditionsGeneration of new project ideas/targets Corporate objectives Previou

12、s experience or knowledge Old mining districts Recent information Literature, including unpublished reports, theses, news releases New developments by other companiesLand Access Is the area open to mineral exploration Who owns the land federal government state government private Indian other Transpo

13、rtationSAMPLING AND ANALYSES How are you going to sample? What are the end-use specifications? What processing must occur?FEASIBILITY STUDYFEASIBILITY STUDY Is this property economic? What are the reserves? Can we mine this property? Can we market this product? What are the environmental consequence

14、s? What is the land status?New technologies are being developed that will increase the chance of finding a new deposit, save money, disturb less land, and minimize affects on local communities and cultures.Geologic methods Robust thermodynamic and kinetic geochemical data and models New ore deposit

15、models, especially for deposits with minimal impact on the environment More sophisticated 3-dimensional geological and ore reserve models Better geohydrologic models relating to mineral deposits, including industrial minerals deposits Geologic maps of mineralized areas Databases of mineral deposits

16、and mineralized areasGeochemical and geophysical methods Hand-held and down-hole analytical instruments Improved cross-bore hole correlation methods and characterization Better understanding of element mobility in soils and water Drones (unmanned aircraft) for airborne geophysical methods Low-cost,

17、seismic methods Better interpretation of remote sensing and hyperspectral data (Livo and Knepper, 2004) More sophisticated 3-dimensional geochemical, hydrological, and geophysical modelsUNMANNED AIRBORNE MAGNETICS (MagSurvey Ltd., http:/www.magsurvey.co.uk/)Drilling technologies Application of exist

18、ing petroleum and geothermal techniques to mineral exploration Improvements in drilling methodsRequired geologic data size, shape, and variability of the ore deposit location information lithology mineralogy-abundance and morphology alteration structural rock competency dataReport on reserves Data D

19、ensity Integration of Geological Information Listing/Recording of Data Set Data Analysis Sample Support Economic Parameters Mineral resource Model Interpolation Method Mineral Resource ValidationEvaluation of potential orebody Ore grade: lots of different units, cut-off grade, homogeneity By-product

20、s: commonly critical to success; Au, Ag, W Commodity prices: forcasting the future Mineralogical form: native vs sulfide vs oxide vs silicate Evaluation of potential orebody Grain size and shape: McArthur River 200Mt, 10%Zn, 4%Pb, 0.2%Cu, 45ppmAg Undesirable substances: As, Sb; calcite in acid leach

21、able U ores Size and shape of deposits: underground vs open pit; Fig 1.16 Ore character: hard vs soft (blasting, wall support) cost and safety Evaluation of potential orebody Cost of capital Location: infrastructure and transportation Environmental considerations: VERY important Taxation: involved s

22、ubject: depreciation, Political factors: nationalization, foreign exchange MINE DEVELOPMENTMINE DEVELOPMENT lower costs site development construction establish infrastructure develop the mine surface (open pit, strip mining) underground (room and pillar, shrinkage stope) solution/leachingPROCESSING/

23、BENEFICIATION/MILLINGOPERATIONSProcessing/beneficiation/milling Extraction/mining crushing (primary, secondary) grinding concentration (gravity separation, flotation, leaching, SX-EW) smelting refiningoptimizes the consumption of energynew technologiesCBMMs new plant for FeNb crushing and packaging

24、(June 1999) is fully automated. Manual handling was eliminated and replaced by a robot.http:/.br/english/sources/mine/operat/f_operat.htmMARKETINGMARKETING Transportation Customer specifications Clean, recyclable and easily transportable Changing marketslow cost productshave high levels of performan

25、ceminimal environmental impactsCLOSURE/POST-MINING USECLOSURE/POST-MINING USE Reclamation Sustaining post-mining use Close-out plansResponsibilities of the geologist Exploration-discovery Feasibility study-ore body evaluation, reserves Mine development-mine design and planning Extraction/production-

26、grade control Processing/beneficiation/milling Marketing-develop a market Closure/post-mining use-environmental geologyJUNIOR COMPANY Property that can be sold to investors High assays Popular commodity Current model Rarely will mine at this level-expects to sell to a mining company MID-SIZE COMPANY

27、 Must have investor appeal Medium to large reserves Short term production at a profit-must generate cash flow May mine if the deposit is small enoughLARGE COMPANY world class orebodyMANUFACTURING AND CHEMCIAL COMPANIES Specific deposits to meet specific product specifications Mines not as important

28、as specifications and long term supplyCLASSIFICATION OF RESERVES AND RESOURCESRESERVES Inferred: That part of a Mineral Resource for which tonnage, grade and mineral content can be estimated with a low level of confidence. Indicated: That part of a Mineral Resource for which tonnage, densities, shap

29、e, physical characteristics, grade and mineral content can be estimated with a reasonable level of confidence. Measured: That part of a Mineral Resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a high level of confidence.RESERVES

30、Probable: The economically mineable part of an Indicated and, in some circumstances, Measured Mineral Resource. Proven: The economically mineable part of a Measured Mineral Resource.“A mineral is where you find it. It may not be the most suitable place in the world.”U.S. Senator Larry Craig, explain

31、ing why he is seeking to lift limits on mine waste dumping onpublic landsIndustrial mineral deposits differ significantly from other, more typical metallic mineral deposits and even amongst themselves.Customer specifications for industrial mineral products are frequently basedsolely on physical prop

32、erties rather than, or in addition to, chemicalcharacteristics.An industrial mineral may have multiple market applications or it may beincluded in multiple end-products. It is essential to determine the physical andchemical characteristics of the industrial mineral in sufficient detail that itsappro

33、priateness for each intended market can be assessed.Determination of the chemical and physical characteristics of an industrial mineral often involves procedures and tests that are not part of the normal activity of an analytical laboratory.The properties of an industrial mineral occurrence can vary

34、 markedly from location to location and even within the same deposit. In particular, many industrial minerals deposits are subject to a nugget effect.Published specifications and standards for industrial minerals should be usedprimarily as a screening mechanism to establish the marketability of an i

35、ndustrial mineral. The suitability of an industrial mineral for use in specific applications can only be determined through detailed market investigations and discussions with potential consumers.GEOLOGY OF INDUSTRIAL MINERALS DEPOSITSGeology provides the framework in which mineral explorationand th

36、e integrated procedures of remote sensing, geophysics,and geochemistry are planned and interpreted.Factors important in evaluating an industrial minerals deposit Customer specifications Distance to customer (transportation) Ore grade-concentration of the commodity in the deposit By-products Commodit

37、y prices Mineralogical form Grain size and shapeFactors-continued Undesirable substances Size and shape of deposit Ore character Cost of capital Location Environmental consequences/ reclamation/bonding Land status Taxation Political factorsTYPES OF MINERAL DEPOSITSEpigenetic mineral depositformed mu

38、ch later than the rocks which enclose it Syngenetic mineral deposit formed at the same time as the rocks that enclose it Why do we classify mineral deposits? Why do we classify mineral deposits? geological conditions of formation how they formed where they formed exploration Simple classification ma

39、gmatic sedimentary supergene metamorphic Deposit Groupshttp:/www.empr.gov.bc.ca/Mining/Geoscience/MineralDepositProfiles/ListbyDepositGroup/Pages/default.aspx Organic Residual/surficial Palcer Continental sediments and volcanics Sediment-hosted Chemical sediment Marine volcanic association Epitherma

40、l Vein, breccia and stockwork Manto Skarn porphyry Ultrmafic/mafic Carbonatites Pegmatites Metamorphic-hosted Gems, semi-precious stones Industrial rocks otherLithology Unconsolidated deposits Sedimentary rocks Volcanic rocks Intrusive rocks Regionally metamorphosed rockshttp:/www.empr.gov.bc.ca/Min

41、ing/Geoscience/MineralDepositProfiles/LithologicalListing/Pages/default.aspxCommodity http:/www.empr.gov.bc.ca/Mining/Geoscience/MineralDepositProfiles/Pages/ListingbyCommodity.aspxClassification of industrial minerals End-use and genesis (Bates, 1960) By unit price and bulk (Burnett, 1962) Unit val

42、ue, place value, representative value (Fisher, 1969) Chemical and physical properties (Kline, 1970) Geologic occurrence and end-use (Dunn, 1973) Geology of origin (Harben and Bates, 1984) Alphabetical (Harben and Bates, 1990, Carr, 1994)Some deposits are formed by more than one process (placers, som

43、e nepheline syenites)Genetic processes that lead to the concentration of mineralsHydrothermal mineral deposits formed in association with magma and water Magmatic mineral deposits concentrated in igneous rocks (crystallization verses segregation) Sedimentary mineral deposits precipitated from a solu

44、tion, typically sea water Placer deposits sorted and distributed by flow of water (or ice) and concentrated by gravity Residual mineral deposits formed by weathering reactions at the earths surfaceGenetic processes-continued Lateral secretion or diffusion of minerals from country rocks into faults a

45、nd other structures Metamorphic processes, both contact and regional Secondary or supergene enrichment where leaching of materials occurs and precipitation at depth produces higher concentrations Volcanic exhalativeHydrothermal mineral deposits formed in association with magma and waterMagmatic mine

46、ral deposits concentrated in igneous rocks (crystallization verses segregation) http:/jove.geol.niu.edu/faculty/fischer/105_info/105_E_notes/lecture_notes/Mineral_Resources/MR_images/pegmatite.jpeghttp:/jove.geol.niu.edu/faculty/fischer/105_info/105_E_notes/lecture_notes/Mineral_Resources/MR_images/

47、kimberlite_pipe.jpeghttp:/pubs.usgs.gov/bul/b2156/b2156.pdfSedimentary mineral deposits precipitated from a solution, typically sea waterhttp:/jove.geol.niu.edu/faculty/fischer/105_info/105_E_notes/lecture_notes/Mineral_Resources/MR_images/death_valley_salt_flats.jpgPlacer deposits sorted and distri

48、buted by flow of water (or ice) and concentrated by gravityBeach placer sandstone deposits are tabular, stratabound REE-Ti-Nb-Zr-Th (U) deposits.Residual mineral deposits formed by weathering reactions at the earths surface-bauxite from AustraliaLateral secretion or diffusion of minerals from countr

49、y rocks into faults and other structuresMetamorphic processes, both contact and regional Skarnshttp:/www.wsu.edu:8080/meinert/Hedley.gifSecondary or supergene enrichment where leaching of materials occurs and precipitation at depth produces higher concentrationsVolcanic massive sulfide depositshttp:

50、/joides.rsmas.miami.edu/files/AandO/Humphris_ODPLegacy.pdfhttp:/joides.rsmas.miami.edu/files/AandO/Humphris_ODPLegacy.pdfShape of ore deposits Tabular Tubular Disseminated Irregular replacement Stratabound Open-space fillingFIELD NOTESField Notes Not writing down your observations could result in mi